Metal lath



H. K. BAKER June 10, 1930.

Filed Oct. 16, 192i Patented June 10, 1930 nan iazaaz HERBERT K. BAKER, OF DETROIT, MICHIGAN, ASSIGNOR T PENN METAL COMIANY, OF CAMBRIDGE, MASSACHUSETTS, A. CORPORATION OF MASSACHUSETTS METAL LATE Applicationfiled October 16, 1925. Serial No. 62,706.

My invention has for its object a metal lath of a novel construction. lhe particular object of the invention is to provide a metal lath which can be made of very thin stock 1 but which will have the requisite rigidity and will be more durable than a lath of the same type as heretofore constructed. The lath embodying my invention 1 is so constructed that the action of the workman in applying the plaster to the face of the lath forces the plaster through the apertures in the lath and causes it to work down over the back face of the longitudinal members thereby covering the rear surface of the longitudinal members 5 so that when the work is completed the lath is protected by a coating of plaster both on the front and on the back. As is well known to those skilled in the art, the present lath has been objectionable because it has been unprotected on the backside and therefore has been subjected to corrosion so that in time the strands of the longitudinal members are eaten through and the lath ceases to support the plaster. To withstand corrosion a metal lath has ordinarily been made of heavier stock than would otherwise be necessary. I have found that by a simple change in construction and without adding to the cost of manufacture, a lathing can be produced which, when plastered on the face, will be embedded in the plaster so that all the strands will be effectively protected from corrosion. My invention, therefore, makes it possible to construct the lathing embodying my invention of thinner gauge material while at the same time having the necessary structural strength and producing a lathing which is as durable as the lathing now commonly in use.

In the drawings:

Fig. 1 is a plan view of a piece of metal lathing embodying my present invention. Fig. 2 is a section on line 2-2, Fig. 1.

Fig. 3 shows the sheet from which the lathing embodying my invention is made, the

sheet being slit.

Fig. l shows the sheet after it has been grooved.

Fig. 5 is a section on line 55, Fig. 1, and

to shows the inclination of the strands.

Fig. 6 is a vertical section and illustrates the action of the lath on the plaster.

The lat-hing is constructed by slitting, ribhing and expanding a sheet of metal of suit able gauge. In Fig. 3 is shown a sheet A 5, which is slit, as shown at 11, in a suitable slitting machine. It is then grooved, as shown at 12 and 13 in Fig. 4:. The grooves 13 are preferably M -shaped in cross section and lie in the slitted area so that when the metal is expanded the narrow longitudinal member lt (see Fig. 1) will have a ll-shaped groove. The wider longitudinal strands 15 are prefcrably given a half-round groove. The grooves serve to stiffen the longitudinal members and increase their strength. After being grooved, the sheet is expanded in the Well-known manner. In expanding the metal, the sheet is left with the narrow longitudinal members 14 in a plane offset from the plane of the broad longitudinal members 15 as shown in Fig. 2 and the connecting strands 16, 16 formed by the slits 11 are not only diagonal when viewed in plan as in Fig. 1 but are inclined as shown in Fig. 5, all the strands being inclined in the same direction. The expanding, to produce the final structure described, may be done by any convenient machine or tools. The final structure has alternate wide and narrow longitudinal members 15 and 14 respectively,.both of these members being grooved or ribbed, and they are connected by diagonal strands 16 as described, there being apertures 17between them.

When the sheet is expanded, the lathing is left with all the narrow longitudinal members 14 in one plane and all the wide longitudinal members 15 in another plane so that between each pair of wide members there is in effect an arch, when the sheet is viewed in 90;. cross section as shown in Fig. 2. This stiffens the sheet lengthwise and helps it to resist the bending due to the weight of the plaster.

When the lath is put in place with the longitudinal members in horizontal position, 95 the narrow members are placed against the furring and the wide members locate them selves a little way from it due to the different planes in which the longitudinal members lie. When the plastering is applied, the movement we of the plasterers tool causes the plastering to work down through each of the apertures above the edge of the wide strands 15, thereby covering the back of each of the wide strands and embedding them in a casing of plaster.

This is shown in Fig. 6. As is well known to those skilled in the art, the workman ordinarily smooths the face of the plaster by moving his smoothing tool in a rotary direction over the plane of the plaster. The inclinations on the strands 16 causes the plaster to work backward lengthwise, tending to embed the strands and the narrow longitudinal members.

I find in actual practice that when the plaster is applied to the metal lath embodying my inveniton, it embeds the back of the lathing much more completely than has been the disposed between each pair of main members, 7

a single series of substantially parallel expanded strands connecting said lntermediate member at each side with a main member and inclining relatively to the intermediate.

member in opposite directions, said intermediate member and strands forming between the main members an arch higher than said shallow ribs.

2. An improved expanded metal lath comprising spaced longitudinal main members grooved to provide relatively shallow ribs, a narrow longitudinal tint-ermediate member disposed between each pair of main members, a single series of substantially parallel expanded strands connecting said intermediate member at each side with a main member and inclining relatively to the intermediate member in opposite directions, said intermediate member and strands forming between the main-members an arch higher than said shallow ribs, and the intermediate member having a longitudinal groove disposed above the plane of said ribs.

3. An expanded metal sheet comprising longitudinally extending main members grooved on one side of the sheet, an intermediate member between each pair of main members displaced out of the general plane of the sheet toward the side at which said grooved portions protrude, said intermediate membersbeing substantially V-shaped and a I singlerow of strands extending from each leg of the V-shaped intermediate members to the adjacent main members, the amount of displacement of the V-shaped intermediate and a single row of strands extending bet tween and connecting adjacent main and intermediate. members, all of said strands being longitudinally inclined with respect to the longitudinally extending members in the general plane of the sheet and the row on one side of any one of said members being oppositely inclined with respect to the row on the other side.

5. An expanded metal sheet comprising longitudinally extending main members grooved on one side of the sheet, an intermediate member between each pair of main members displaced out of the general plane of the sheet toward the side at which said grooved portions protrude a distance greater than the depth of the said grooved portions and a single row of strands extending between and connecting adjacent main and intermediate members, all of said strands being longitudinally inclined with respect to the longitudinally extending members and transversely inclined with respect to the plane of the sheet.

In testimony whereof I afiix my signature.

HERBERT K. BAKER. 

